1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a method of fabricating a capacitor of a semiconductor device which increases the effective area of the capacitor in a highly integrated device, increasing the capacitance.
2. Discussion of the Related Art
Generally, capacitors in semiconductor devices are divided into stacked types and trench types. The stacked capacitors are divided into fin structures, cylinder structures, and box structures. The cylinder-structure capacitor has the storage node electrode in the form of cylinder. Memory devices of 64 Mbit and higher generally employ the cylinder-structure capacitor for effectively increasing the capacitance.
A conventional method of fabricating a capacitor of a semiconductor device is explained below with reference to the accompanying drawings. FIGS. 1A, 1B and 1C are cross-sectional views showing the conventional fabrication steps for a capacitor of a semiconductor device.
Referring to FIG. 1A, an interlevel insulating layer 2 is formed on a semiconductor substrate 1 on which cell transistors (not shown) are also formed. The insulating interlayer 2 is then selectively removed, forming a storage node contact hole. A first polysilicon layer 3 is formed on the overall surface of the substrate 1 in order to bury the storage node contact hole. An oxide layer 4 is formed on the first polysilicon layer 3.
Referring to FIG. 1B, the oxide layer 4 is selectively removed through photolithography, and the first polysilicon layer 3 is selectively etched using the patterned oxide layer 4 as a mask. Referring to FIG. 1C, a second polysilicon layer 5 (used for forming a pillar layer of a storage node) is formed on the overall surface of the substrate including the oxide layer 4 and the first polysilicon layer 3. Then, the second polysilicon layer 5 is etched back and remains only on the sides of the oxide layer 4 and the first polysilicon layer 3. The oxide layer 4 is removed through wet etching, completing the storage node of a capacitor.
Thereafter, a dielectric layer (not shown) is formed on the storage node, and a plate electrode (not shown) is formed thereon, completing the capacitor. In the conventional method of fabricating a capacitor, it is possible to form the storage node having curved portions by repeatedly depositing and patterning the oxide layers, thus increasing the capacitance. However, this method of fabrication of capacitors is disadvantageously complicated.